/Engine/Source/Runtime/Engine/Classes/Animation/AnimInstance.h
Return true if this instance playing the slot animation, also returning the montage it is playing on
bool IsPlayingSlotAnimation ( const [UAnimSequenceBase](API\Runtime\Engine\Animation\UAnimSequenceBase) * Asset, [FName](API\Runtime\Core\UObject\FName) SlotNodeName, [UAnimMontage](API\Runtime\Engine\Animation\UAnimMontage) *& OutMontage ) const